Clean gas purge for breathing gas regulator

Abstract

A self contained breathing apparatus (SCBA) served by a source of breathing gas with a mask and a demand regulator connected to the mask. The regulator has a flexible diaphragmatic member having a side exposed to ambient that moves in response to pressure differentials to cause a valve mechanism to introduce breathing gas to the mask. A passage provides breathing gas over said diaphragm exposed to ambient which can be a passage from one side of the diaphragm to the other. A protective cover can overlie the passage which can be displaced upon gas flow through the passage. The method purges ambient contaminants from the diaphragm by providing breathing gas over the diaphragm through an opening of the diaphragm.

1. A self contained breathing apparatus (SCBA) having a
 demand regulator comprising: 
 a source of breathing gas; 
 a mask with a lens; 
 a demand regulator connected to said mask and said source of breathing gas; 
 a flexible member in said demand regulator that moves in response to pressure differentials, said flexible member being at least in part formed of an elastomer, said flexible member having an outside portion exposed to ambient with an opposite inside portion of said flexible member in fluid communication with a user; 
 a valve for introducing breathing gas through said regulator to said mask connected for movement in response to movement of said flexible member; 
 a passage for providing breathing gas over the outside of said flexible member, said passage being formed as an opening from the inside of said flexible member to the outside; and 
 a cover overlying said passage which can be displaced upon breathing gas flowing through said passage. 
 
   
   
     2. The SCBA as claimed in  claim 1  further comprising:
 said cover is an elastomeric member; and, said flexible member is a diaphragm. 
 
   
   
     3. The SCBA as claimed in  claim 1  further comprising:
 said flexible member is at least in part a diaphragm; and, 
 said regulator when in use maintains a pressure above ambient in said mask and on the inside of said diaphragm. 
 
   
   
     4. The SCBA as claimed in  claim 3  further comprising:
 said passage provides flow over the outside of said diaphragm when said regulator is in use; and, 
 an outlet is connected to the outside of said diaphragm for allowing flow from said passage to the ambient. 
 
   
   
     5. The SCBA as claimed in  claim 4  wherein:
 said cover is at least in part a flexible disk like member over said passage that allows flow thereunder when breathing gas flow is provided through said passage. 
 
   
   
     6. A self contained breathing apparatus (SCBA) having a demand regulator comprising:
 a source of breathing gas; 
 a mask with a lens; 
 a demand regulator connected to said mask and said source of breathing gas; 
 a flexible member in said demand regulator that moves in response to pressure differentials, said flexible member being at least in part formed of an elastomer and being at least in part a diaphragm, said flexible member having an outside portion exposed to ambient with the opposite inside portion of said flexible member in fluid communication with a user; 
 a valve for introducing breathing gas through said regulator to said mask connected for movement in response to movement of said flexible member; 
 a passage for providing breathing gas over the outside of said flexible member, said passage being formed as an opening from the inside of said flexible member to the outside, said passage providing flow over the outside of said diaphragm when said regulator is in use; 
 said regulator when in use maintaining a pressure above ambient in said mask and on the inside of said diaphragm; 
 an outlet is connected to the outside of said diaphragm for allowing flow from said passage to the ambient; and, 
 a flexible disk like member over said passage that allows flow thereunder when breathing gas flow is provided through said passage. 
 
   
   
     7. The SCBA as claimed in  claim 6 , wherein:
 at least a portion of said flexible disk like member can be displaced upon breathing gas flowing through said passage. 
 
   
   
     8. The SCBA as claimed in  claim 7  further comprising:
 said flexible disk like member is an elastomeric member; and, said flexible member is a diaphragm. 
 
   
   
     9. A demand breathing gas regulator comprising:
 a regulator body for fluid connection to a user's mask and a source of breathing gas; 
 a flexible member operably connected to a breathing gas demand valve supported by said regulator body, said flexible member being at least in part formed of a diaphragm, said flexible member having one side exposed to ambient through an opening in said regulator; 
 a passage for delivery of breathing gas over a face of said flexible member exposed to ambient, said passage being formed through said flexible member; and, 
 a cover overlying said passage which moves in response to breathing gas flowing through said passage. 
 
   
   
     10. A self contained breathing apparatus (SCBA) comprising:
 a tank for containment of breathing gas; 
 a first stage regulator fluidically connected to said tank; 
 a second stage regulator fluidically connected to said first stage regulator; 
 a mask fluidically connected to said second stage regulator; 
 a diaphragm in said second stage regulator having an outside portion exposed to ambient with the opposite inside portion of said diaphragm in fluid communication with a user; 
 a pilot valve fluidically connected to a second valve for causing flaw of breathing gas, said pilot valve being located on the inside of said regulator for providing breathing gas at a pressure above ambient; and 
 a passage through said diaphragm from the inside portion thereof to provide breathing gas on the outside of said diaphragm. 
 
   
   
     11. A self contained breathing apparatus (SCBA) comprising:
 a tank for containment of breathing gas; 
 a first stage regulator fluidically connected to said tank; 
 a second stage regulator fluidically connected to said first stage regulator; 
 a mask fluidically connected to said second stage regulator; 
 a diaphragm in said second stage regulator having an outside portion exposed to ambient with an opposite inside portion of said diaphragm in fluid communication with a user; 
 a valve operably connected to the diaphragm on an inside of said second stage regulator for providing breathing gas at a pressure above ambient; 
 a passage through said diaphragm from the inside portion thereof to provide breathing gas on the outside portion of said diaphragm; and 
 a cover overlying said passage which allows flow from said passage when breathing gas flows therethrough. 
 
   
   
     12. The SCBA as claimed in  claim 11 , wherein: said diaphragm and said cover are comprised at least in part of an elastomeric material. 
   
   
     13. A method for providing regulated breathing gas through a demand regulator comprising:
 providing a source of breathing gas; 
 regulating said breathing gas to an intermediate pressure by a first stage regulator; 
 conducting said intermediate pressure gas to a demand regulator; 
 regulating said intermediate pressure by a demand regulator having a flexible member exposed on one side to ambient and on an opposite side to breathing gas, said intermediate pressure being regulated by a valve mechanism connected to said flexible member, 
 passing said breathing gas over the one side of said flexible member exposed to ambient; 
 allowing said breathing gas to flow from the opposite side of said flexible member to the side exposed to ambient; and 
 covering said flexible member at least in part when breathing gas is not passing to the side exposed to ambient. 
 
   
   
     14. The method as claimed in  claim 13  further comprising:
 said flexible member is formed at least in part from an elastomer. 
 
   
   
     15. A method of purging ambient contaminants from a demand breathing gas regulator comprising:
 providing a demand regulator served by a source of breathing gas, said demand regulator having a flexible member exposed on one side to ambient conditions and on an opposite side to the breathing gas, said flexible member being at least in part an elastomeric diaphragm; 
 passing breathing gas to the side of said flexible member exposed to ambient and purging at least in part any contaminants from said flexible member by the flow of said gas, said breathing gas being passed through an opening of said diaphragm; and, 
 covering said opening when breathing gas is not passing therethrough. 
 
   
   
     16. The method as claimed in  claim 15  wherein:
 said diaphragm is covered by a disc. 
 
   
   
     17. A demand breathing gas regulator comprising:
 a regulator body for fluid connection to a user's mask and a source of breathing gas; 
 a flexible member operably connected to a breathing gas demand valve supported by said regulator body, said flexible member having one side exposed to ambient through an opening in said regulator; 
 a passage for delivery of breathing gas over a face of said flexible member exposed to ambient; 
 a cover overlying said passage, at least a portion of said cover being displaced upon flow of breathing gas through said passage; 
 a pilot valve of said regulator that moves in response to pressure differentials on said flexible member; and, 
 a second valve which valves breathing gas through said regulator in response to said pilot valve.